This Nonprovisional application claims priority under 35 U.S.C. §119(a) on patent Application No.2003-041395 filed in Japan on Feb. 19, 2003, the entire contents of which are hereby incorporated by reference.
The present invention pertains to an original transport apparatus for taking up one or more original sheets one sheet at a time and transporting same during image capture.
Conventionally known techniques for capturing images of originals include two capturing methods, these being stationary-original capture and moving-original capture.
Because the stationary-original capture method is such that capture takes place with the original being held stationary and with scanning being accomplished through movement of the image information capture component (optical unit), this is suitable where the original is a book or is card stock. There is also the advantage that because scanning is performed by an image information capture component (optical unit), the precision with which capture takes place can easily be increased.
In contrast thereto, because the moving-original capture method is such that capture takes place with the image information capture component (optical unit) being held stationary and with scanning being accomplished through movement of the original, this has the advantage that the apparatus can be reduced in size, and also that the area occupied by the apparatus can be made small; e.g., when the apparatus is employed in an image forming apparatus. Furthermore, if a number of originals are placed together in the original tray, there is the significant advantage that because capture takes place automatically with these being taken up one sheet at a time, a large quantity of originals can be captured in a short period of time with little inconvenience to the operator.
Furthermore, with the moving-original capture method, whereas the number of original sheets that could be placed in the original tray at a single time was previously on the order of 20 to 40 sheets, it has in recent years become possible to place somewhere in the neighborhood of 100 sheets therein. This has been made possible due in part to improved printing speed, increased memory capacity of the controller provided within the capturing apparatus which temporarily stores image data, improved controller processing speed, and so forth.
However, where the number of original sheets placed therein increases as has been stated to be the case, the likelihood that any given set of stacked originals (one job) can be transported and captured without incident decreases. Furthermore, where an original capturing apparatus is used in combination with an image forming apparatus as a copier, occurrence of a problem at the image forming apparatus will also cause operations at the original capturing apparatus to be temporarily stopped. In the event that an original becomes stuck in this way somewhere along the original transport path, it will be necessary to remove that original.
Now, there are arrangements in which a stopper member for stopping original lead edges and blocking off the near side of the transport path is arranged at an original tray so as to align lead edges and prevent skewing of originals loaded in an inclined original tray while withstanding the weight of such originals during the period prior to initiation of transport of the first original from the original tray, while also preventing situations such as those in which originals accidentally enter the transport path and cause multiple sheets to be transported in conjunction with initiation of transport (see, e.g., Japanese Patent Application Publication Kokai No. 2001-199584).
With an original tray such as is described in such places as this Japanese Patent Application Publication Kokai No. 2001-199584, in the event that an original becomes stuck somewhere along the original transport path, it will as has been described above be necessary to remove that original therefrom, but because it has not conventionally been possible to open and close the outer casing thereof, retrieval of originals therefrom has been troublesome. Accordingly, there has been a need to implement operations such as would permit opening and closing of the outer casing so as to facilitate retrieval of originals which have become stuck therein.
But in constitutions in which a stopper member such as is described in the aforementioned Japanese Patent Application Publication Kokai No. 2001-199584 is, for example, provided at the outer casing, implementation of operations for opening and closing the outer casing can sometimes result in situations in which opening of the outer casing causes originals to slide down the original tray under the force of their own weight and to be displaced from original loading location(s), resulting in alteration of the timing with which originals are taken up thereinto and so forth. Furthermore, when an attempt is made to close the outer casing, a new problem can occur in which the stopper member comes in contact with the leading edges of originals sliding down thereonto, piercing and damaging originals in a worst-case scenario.
The situation will be described in detail with reference to the original transport apparatus of constitution as shown in FIGS. 21 through 25. Note that FIGS. 21 through 24 are vertical sectional views of the original transport apparatus, and FIG. 25 is a schematic plan view thereof.
Outer casing 1, which houses pickup roller R1 and separation roller R2, is such that the basal side thereof (the right side in the drawing) is supported by shaft 2, disposed in a direction perpendicular to the original transport direction, so as to permit opening and closing about a horizontal axis; shaft 2 disposed in a direction perpendicular to transport direction X of original 11 serving as center of rotation during opening and closing. Furthermore, at the free side (the left side in the drawing) of outer casing 1, stopper member 4 is supported by shaft 3, disposed in a direction perpendicular to transport direction X, so as to permit displacement in pivoting fashion.
Furthermore, in the region of an edge at the basal side of outer casing 1, separation roller R2 is rotatably supported by support pin 5, which is disposed in a direction perpendicular to transport direction X; one end of pickup arm 6 being supported by this support pin 5 so as to permit displacement in pivoting fashion. Furthermore, at the other end of pickup arm 6, pickup roller R1 is rotatably supported by support pin 7, which is disposed in a direction perpendicular to transport direction X.
Moreover, post 8 is provided at outer casing 1, engagement piece 9 being supported by this post 8 by means of support pin 9c so as to permit displacement in pivoting fashion. Furthermore, engagement finger 9a, provided in the region at one end of this engagement piece 9, engages with engagement finger 4a provided in the region of the top end of stopper member 4, causing stopper member 4 to be retained such that it is roughly vertical. As a result, stopper member 4, as has been described, blocks the near side of transport path 12 so as to align lead edges 11a of originals 11 loaded in original tray 10 while withstanding the weight of such originals 11, and also prevents originals 11 from accidentally entering transport path 12.
Moreover, protruding horizontally from the region at the other end of engagement piece 9 is thrust pin 9b, this thrust pin 9b being pushed on and driven by thrust piece 6b, which is provided in the region at one end of pickup arm 6.
At this engagement piece 9, the weight to the engagement finger 9a side of support pin 9c is greater than the weight to the thrust pin 9b side thereof. Accordingly, when thrust piece 6b is not in contact with thrust pin 9b, i.e., when pickup arm 6 is in its raised position (the situation shown in FIG. 21), the aforementioned weight distribution causes the engagement finger 9a side thereof to be displaced downward in pivoting fashion, so that engagement finger 9a engages with engagement finger 4a of stopper member 4 as described above.
FIG. 25 is a schematic plan view of an original transport apparatus constituted as described above.
Disposed more or less centrally in the width direction of outer casing 1 of this original transport apparatus is pickup arm 6 possessing pickup roller R1 and separation roller R2; furthermore, stopper members 4 and engagement pieces 9, constituted as described above, are respectively arranged at locations outward from, and to either side in the width direction of, this pickup arm 6. That is, stopper members 4 and engagement pieces 9 are disposed at locations outward from pickup arm 6 such that a pair of each respectively straddles pickup arm 6.
Furthermore, provided at one side of pickup arm 6 is drive control means which drives pickup arm 6 so as to displace it in pivoting fashion, this drive control means being primarily made up of electromagnetic clutch 81, torque limiter 82, and pickup arm spring 83. That is, engagement and disengagement of drive is carried out by electromagnetic clutch 81, pickup arm 6 being driven in pivoting fashion by virtue of the force at torque limiter 82. Furthermore, the restoring force from pickup arm spring 83 is always acting on pickup arm 6 in a direction tending to raise it upward, so that, at times when there is no force acting at torque limiter 82, the restoring force from this pickup arm spring 83 causes pickup arm 6 to be raised and assume a prescribed position within outer casing 1.
FIG. 21 shows the situation described above which exists when engagement finger 4a of stopper member 4 is engaged with engagement finger 9a of engagement piece 9, and the near side of transport path 12 is blocked off.
When capture of originals is initiated with the apparatus in this state, the aforementioned drive control means, as shown in FIG. 22, causes pickup arm 6 to pivot as indicated by the arrow at reference numeral 91, and pickup roller R1 comes in contact with the topmost sheet(s) among originals 11, taking up the topmost original sheet. Furthermore, pivoting displacement of this pickup arm 6 causes thrust piece 6b to press down on and lower thrust pin 9b, causing the engagement finger 9a side of engagement piece 9 to rise up as indicated by the arrow at reference numeral 92, and causing the two engagement fingers 9a, 4a which had been mutually engaged to become disengaged. Accordingly, as the taking up of topmost original sheet(s) 11a proceeds, the lead edge(s) of such original(s) 11a cause stopper member 4 to be lifted up as indicated by the arrow at reference numeral 93, opening up access to transport path 12, whereupon separation roller R2 and separation plate 16 cause only a single sheet to be selectively extracted from original(s) 11a, and this is then guided toward an original capturing unit, not shown.
With a constitution such as has been described, when outer casing 1 is opened due to occurrence of a transport problem as shown in FIG. 23, originals 11 slide down original tray 10 under the force of their own weight and are displaced from original loading location(s). Furthermore, when outer casing 1 is opened, engagement finger 4a of stopper member 4, which is raised up thereto in accompaniment to movement of outer casing 1, engages with engagement finger 9a of engagement piece 9, engagement piece 9 having been in its freed orientation.
With the apparatus in this state, closing outer casing 1 as indicated by the arrow at reference numeral 94 causes the problematic situation shown in FIG. 24 in which the bottom region of stopper member 4 abuts originals 11 during closing of that outer casing 1 and forces its way past originals 11.
The present invention was conceived in order to solve such problems, it being an object thereof to provide an original transport apparatus capable of mitigating problems associated with stopper member(s) occurring in conjunction with opening and/or closing of outer casing(s) without interfering with intended function of stopper member(s) (ability to constrain original lead edge(s) when original(s) is/are loaded).